Polyaxial screw and locking cap

ABSTRACT

Systems, methods, and devices for securing a spinal rod are provided. A clamp assembly comprises a tulip comprising an opening comprising an inner surface, wherein the inner surface is threaded; and a threaded locking cap disposed in the opening, wherein threads of the locking cap and the inner surface include various geometries.

BACKGROUND

Many types of spinal irregularities cause pain, limit range of motion,or injure the nervous system within the spinal column. Theseirregularities can result from trauma, tumor, disc degeneration, ordisease. Typically, these irregularities are treated by immobilizing aportion of the spine. This treatment typically involves affixing aplurality of components, such as, for example, screws, hooks, and/orclamps, to one or more vertebrae, and attaching the components to anelongated rod that stabilizes the vertebrae.

SUMMARY

In an exemplary embodiment, the present disclosure provides a clampassembly comprising a tulip comprising an opening comprising an innersurface, wherein the inner surface is threaded; and a threaded lockingcap disposed in the opening, wherein threads of the locking cap and theinner surface include various geometries.

In another exemplary embodiment, the present disclosure provides a clampassembly comprising a tulip comprising an opening comprising an innersurface, wherein the inner surface is threaded; and a threaded lockingcap disposed in the opening, wherein the threaded locking cap includes adrive feature, wherein the drive feature includes various geometries.

In another exemplary embodiment, the present disclosure provides a clampassembly comprising a tulip, wherein an inner surface of the tulipcomprises threads; and a drive feature positioned in an outer portion ofthe tulip, the drive feature configured to receive a driving instrument,wherein the drive feature includes various geometries.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory innature and are intended to provide an understanding of the presentdisclosure without limiting the scope of the present disclosure. In thatregard, additional aspects, features, and advantages of the presentdisclosure will be apparent to one skilled in the art from the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments ofthe present disclosure and should not be used to limit or define thedisclosure.

FIG. 1 illustrates a clamp assembly in accordance with particularembodiments of the present disclosure;

FIG. 2 illustrates square threads of a clamp assembly in accordance withparticular embodiments of the present disclosure;

FIG. 3A illustrates a first type of buttress threads of a clamp assemblyin accordance with particular embodiments of the present disclosure;

FIG. 3B illustrates a second type of buttress threads of a clampassembly in accordance with particular embodiments of the presentdisclosure;

FIG. 3C illustrates a bottom positive angle thread of a clamp assemblyin accordance with particular embodiments of the present disclosure;

FIG. 4A illustrates a top view of a drive feature of a threaded lockingcap in accordance with particular embodiments of the present disclosure;

FIG. 4B illustrates a top view of another drive feature of a threadedlocking cap in an initial position in accordance with particularembodiments of the present disclosure;

FIG. 5 illustrates a side cross-sectional view of another threadedlocking cap and driving instrument in accordance with particularembodiments of the present disclosure;

FIG. 6 illustrates a side cross-sectional view of another threadedlocking cap and insertion instrument in accordance with particularembodiments of the present disclosure;

FIG. 7 illustrates a side view of a clamp assembly in accordance withparticular embodiments of the present disclosure;

FIG. 8 illustrates a side view of another clamp assembly in accordancewith particular embodiments of the present disclosure;

FIG. 9 illustrates a side cross-sectional view of another clamp assemblyin accordance with particular embodiments of the present disclosure;

FIG. 10 illustrates a side view of another clamp assembly in accordancewith particular embodiments of the present disclosure;

FIG. 11 illustrates a side view of another locking cap in accordance inaccordance with particular embodiments of the present disclosure;

FIG. 12 illustrates a portion of another locking cap in accordance withparticular embodiments of the present disclosure;

FIG. 13 illustrates a clamp assembly in accordance with particularembodiments of the present disclosure;

FIG. 14 illustrates a tulip in accordance with particular embodiments ofthe present disclosure;

FIG. 15 illustrates another tulip in accordance with particularembodiments of the present disclosure;

FIG. 16A illustrates a side cross-sectional view of a clamp assembly inaccordance with particular embodiments of the present disclosure;

FIG. 16B illustrates a side cross-sectional view of another clampassembly in accordance with particular embodiments of the presentdisclosure;

FIG. 16C illustrates a side cross-sectional view of another clampassembly in accordance with particular embodiments of the presentdisclosure;

FIG. 17A illustrates a tulip in accordance with particular embodimentsof the present disclosure;

FIG. 17B illustrates a saddle in accordance with particular embodimentsof the present disclosure;

FIG. 18 illustrates a side cross-sectional view of another clampassembly in accordance with particular embodiments of the presentdisclosure;

FIG. 19A illustrates a side cross-sectional view of another clampassembly in accordance with particular embodiments of the presentdisclosure;

FIG. 19B illustrates a perspective view of a saddle in accordance withparticular embodiments of the present disclosure;

FIG. 20A illustrates a bottom view of a tulip in accordance withparticular embodiments of the present disclosure;

FIG. 20B illustrates a bottom view of a tulip with a bone screw inaccordance with particular embodiments of the present disclosure;

FIG. 21A illustrates a clamp assembly with a bone screw in accordancewith particular embodiments of the present disclosure;

FIG. 21B illustrates a bone screw in accordance with particularembodiments of the present disclosure;

FIG. 22A illustrates a perspective view of a clamp assembly with apivoting bone screw in accordance with particular embodiments of thepresent disclosure;

FIG. 22B illustrates a side cross-sectional view of a clamp assemblywith a bone screw in accordance with particular embodiments of thepresent disclosure;

FIG. 23 illustrates a one-piece tulip and bone screw in accordance withparticular embodiments of the present disclosure;

FIG. 24A illustrates a side cross-sectional view of a clamp assembly inaccordance with particular embodiments of the present disclosure;

FIG. 24B illustrates a top view of a head of a bone screw in accordancewith particular embodiments of the present disclosure;

FIG. 25A illustrates a portion of an inner surface of a tulip inaccordance with particular embodiments of the present disclosure;

FIG. 25B illustrates a portion of an inner surface of another tulip inaccordance with particular embodiments of the present disclosure;

FIGS. 26A-26K illustrate various geometries of an upper portion of atulip in accordance with particular embodiments of the presentdisclosure;

FIGS. 27-29 illustrate various features positioned on an outer surfaceof a tulip in accordance with particular embodiments of the presentdisclosure;

FIG. 30 illustrates a clamp assembly with break off portions inaccordance with particular embodiments of the present disclosure;

FIG. 31A illustrates a clamp assembly with a cable in accordance withparticular embodiments of the present disclosure; and

FIG. 31B illustrates a tulip with a cable positioned about a spinal rodin accordance with particular embodiments of the present disclosure.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the implementationsillustrated in the drawings and specific language will be used todescribe them. It will nevertheless be understood that no limitation ofthe scope of the disclosure may be intended. Any alterations and furthermodifications to the described devices, instruments, methods, and anyfurther application of the principles of the present disclosure arefully contemplated as would normally occur to one skilled in the art towhich the disclosure relates. In particular, it may be fullycontemplated that the features, components, and/or steps described withreference to one or more implementations may be combined with thefeatures, components, and/or steps described with reference to otherimplementations of the present disclosure. For simplicity, in someinstances the same reference numbers are used throughout the drawings torefer to the same or like parts.

Embodiments generally relate to spinal surgery. More particularly,embodiments relate to systems, methods, and devices for securing aspinal rod and a pedicle screw with a clamp assembly.

The clamp assembly can be utilized for open and percutaneous approachesto the posterior spine. The clamp assembly can be used on multiple typesof pedicle screws such as polyaxial, uniplanar, monoaxial, reduction,and modular pedicle screws. The clamp assembly locks or restricts motionof the pedicle screw and the spinal rod. This allows corrective forcesto transfer to vertebra for axial derotation, parallel compression,parallel distraction, and/or reduction.

FIG. 1 illustrates a clamp assembly (“clamp assembly”) 100 in accordancewith particular embodiments of the present disclosure. In theillustrated embodiment, the clamp assembly 100 may include a tulip 102and a threaded locking cap 114 disposable in the tulip 102. A pediclescrew 115 may extend from a bottom portion of the tulip 102. Asillustrated, a spinal rod 118 may be held by the tulip 102. Bytightening the threaded locking cap 114 into the tulip 102, a spinal rod118 and pedicle screw 115 may be secured in the tulip 102.

The tulip 102 may be a rigid member that resembles a bullet with ahollow interior. The tulip 102 may include an opening 104 situatedbetween portions 106 a and 106 b. A curved portion 108 may be disposedbetween the portions 106 a and 106 b, as shown. The curved portion 108may be curved to correspond with a shape of a spinal rod 118. Asillustrated, the portions 106 a and 106 b may be in the form of tabsthat extend generally parallel away from the curved portion 108 todistal ends 110 a and 110 b. In certain embodiments, the opening 104 maybe defined between the portions 106 a and 106 b. In certain embodiments,the opening 104 may extend from the curved portion 108 to distal ends110 a and 110 b of the portions 106 a and 106 b, as shown. Inner surface112 of the portions 106 a and 106 b may be threaded.

The threaded locking cap 114 may be disposed within the opening 104, asshown. The spinal rod 118 may extend through the opening 104, and ascrew such as the pedicle screw 115 may extend through the curvedportion 108. As illustrated, the pedicle screw 115 (or a portionthereof, such as the screw head) may extend into the curved portion 108of the tulip 102. In accordance with particular embodiments, tighteningthe threaded locking cap 114 should a saddle component when thencompresses against the pedicle screw 115 to restrict motion of thespinal rod 118 and the pedicle screw 115 thereby forming a rigidconstruct.

Various thread geometries can be used for the inner surface 112 of thetulip 102 and the threaded locking cap 114. Suitable thread geometriesmay include, but are not limited to, rectangular shaped threads and/orangled threads. FIGS. 2, 3A, 3B, and 3C will describe different threadgeometries in accordance with particular embodiments.

FIG. 2 illustrates threads 200 of the inner surface 112 and threads 202of the threaded locking cap 114 in accordance with particularembodiments of the present disclosure. As shown, the threads 200 and 202are straight or rectangular shaped (e.g., square shaped).

FIG. 3A illustrates threads 300 a (e.g., buttress threads) of an innersurface 112 a and threads 302 a of a threaded locking cap 114 a inaccordance with particular embodiments of the present disclosure. Asshown, a bottom surface 304 a of a thread 302 a may be angled outwardaway from a minor diameter 306 a. A top surface 308 a may be flat orangled inward (e.g., top surface 308 b shown on FIG. 3B), towards theminor diameter 306 a.

FIG. 3B illustrates threads 300 b (e.g., buttress threads) of an innersurface 112 b and threads 302 b of a threaded locking cap 114 b inaccordance with particular embodiments of the present disclosure. Asshown, a bottom surface 304 b of a thread 302 b may be angled outwardaway from a minor diameter 306 b. A top surface 308 b may be flat orangled inward towards the minor diameter 306 b.

FIG. 3C illustrates threads 300 c of an inner surface 112 c and threads302 c of a threaded locking cap 114 c in accordance with particularembodiments of the present disclosure. As shown, a bottom surface 304 cof a thread 302 c may be angled inward to a minor diameter 306 c. A topsurface 308 c may angled inward or flat.

In accordance with present embodiments, a driving instrument (e.g.,driving instrument 500 on FIG. 5 or driving instrument 602 on FIG. 6)may be used to drive the locking cap 114 into the tulip 104. The lockingcap 114 may be include various design features for engagement with thedriving instrument. FIGS. 4A and 4B illustrate various drive features onthe locking cap 114 into which the driving instrument may be inserted inaccordance with particular embodiments. FIGS. 5 and 6 illustrate variousfeatures that may be used for retainment of the locking cap 114 by thedriving instrument in accordance with particular embodiments. Thelocking cap 114 may also include various features for contact with thetulip 104. FIGS. 7 to 11 illustrate various features of the locking cap114 for contact with the tulip 104.

FIG. 4A illustrates a locking cap drive feature (“drive feature”) 400 afor a locking cap 114 d, in accordance with particular embodiments ofthe present disclosure. The drive feature 400 a may be used to insertand tighten the locking cap 114 d, and may be a hex, a hexalobe (asshown), or a modified hexalobe (e.g., shown on FIG. 4B). The drivefeature 400 a may either go partway into or through the locking cap 114d. The drive feature 400 a may be formed in a top of the locking cap 114d. In the illustrated embodiment, the drive feature 400 a is recessed,but it should be understood the drive feature 400 a may also be aprotrusion from the locking cap 114 d.

FIG. 4B illustrates a locking cap drive feature (“drive feature”) 400 bfor a locking cap 114 e, in accordance with particular embodiments ofthe present disclosure. The drive feature 400 b may be used to insertand tighten the locking cap 114 e, and may be a hex, a hexalobe, or amodified hexalobe (as shown). The modified hexalobe has inner lobes 402of a hexalobe truncated by a circle. The drive feature 400 b may eithergo partway into or through the locking cap 114 e. The drive feature 400b may be formed in a top of the locking cap 114 e. In the illustratedembodiment, the drive feature 400 b is recessed, but it should beunderstood the drive feature 400 a may also be a protrusion from thelocking cap 114 e.

FIG. 5 illustrates a cross-section of a driving instrument 500positioned within a locking cap 114 f in accordance with particularembodiments of the present disclosure. As shown, the locking cap 114 fmay include grooves 501 to receive spring tabs 502 of a drivinginstrument 501. The spring tabs 502 may clip into the grooves 500 of thelocking cap 114 f, for example, to secure the driving instrument 500 tothe locking cap 114 f. In certain embodiments (not shown), the lockingcap 114 f can be retained instead by a tapered drive feature on eitherthe locking cap 114 f, the driving instrument 501, or both.

FIG. 6 illustrates a cross-section of a split ring 600 housed on adriving instrument 602 in accordance with particular embodiments of thepresent disclosure. The split ring 600 may be used, for example, tosecure the driving instrument 602 to the locking cap 114 g. As shown,the split ring 600 may exert radial pressure against a drive feature 604of a locking cap 114 g to retain the locking cap 114 g. In certainembodiments, a groove (not shown) may be cut into the the drive feature604 for the split ring 600 to expand into for further retention. Thelocking cap 114 g may include a flat bottom 606, as shown.

FIG. 7 illustrates a locking cap 114 h disposed within the tulip 102, inaccordance with particular embodiments of the present disclosure. Asshown, a bottom 700 of the locking cap 114 h may be flat but have anarrower outer diameter 701 than a minor diameter 702 of threads 703, toprovide a more consistent contact with a curvature of the spinal rod118. However, while FIG. 7 shows the bottom 700 as being flat, it shouldunderstood that embodiments of the bottom 700 may be otherwise formed,for example, curved or angled.

FIG. 8 illustrates a locking cap 114 i disposed within the tulip 102, inaccordance with particular embodiments of the present disclosure. Asshown, a bottom 800 of the locking cap 114 i may have a rounded bump 802to contact the spinal rod 118 at a point 804. The bump 802 may deform orindent the spinal rod 118 or be deformed by the spinal rod 118 toincrease grip. The bump 802 may extend from a minor portion of thebottom 800 of the locking cap 114 i.

FIG. 9 illustrates a cross-section of a locking cap 114 j disposedwithin a tulip 102, in accordance with particular embodiments of thepresent disclosure. A bottom 900 of the locking cap 114 j may have arounded ring 900 to contact the spinal rod 118 at two points 902 and904. The rounded ring 900 may deform or indent to increase grip. In someembodiments, the rounded ring 900 may be raised portion of the bottom900 of the locking cap 114 j.

FIG. 10 illustrates a locking cap 114 k disposed within the tulip 102 inaccordance with particular embodiments of the present disclosure. Abottom 1000 of the locking cap 114 k may have a groove 1002 cut into itthat seats on the spinal rod 118 as the locking cap 114 k rotates to itsfinal tightening state. The groove 1002 may have profile, for example,the matches a profile of the spinal rod 118.

FIG. 11 illustrates a locking cap 114L in accordance with particularembodiments of the present disclosure. As shown, a contact surface 1100for the spinal rod 118 (e.g. shown on FIG. 10) is a separate componentto allow the contact surface 1100 to be made from a different materialor surface finish from the locking cap 114L. As illustrated, the contactsurface 1100 may be attached to a bottom of the locking cap 114L. Thecontact surface 1100 may be shaped to any of the previously describedembodiments. Any suitable technique may used for attachment of thecontact surface 1100 to the locking cap 114L, including, but not limitedto, adhesives, welding, locking features, and/or fasteners, amongothers.

Additional features may be included on the locking cap 114. For example,features may be included on the locking cap that increase engagement ofthe locking cap 114 with the tulip 114 more efficient for installation.FIGS. 12 and 13 illustrate different features that may be included onthe locking cap 114 for increasing engagement with the tulip 104.

FIG. 12 illustrates a portion of a locking cap 114 m in accordance withparticular embodiments of the present disclosure. As shown, a firstthread 1204 at a bottom 1202 of the locking cap 114 m is broken by aradiused cut 1200 The radiused cut 1120 from the first thread 1200 mayincrease the strength of the first thread 1200 as it is being engagedand to prevent cross-threading of the locking cap 114 m.

FIG. 13 illustrates a clamp assembly 1300 in accordance with particularembodiments of the present disclosure. A start 1302 of threads 1304 in alocking cap 114 n and a start 1306 of threads 1308 in an inner surface112 d of a tulip 1310 are timed with corresponding markings such as, forexample, cutouts 1303 of the locking cap 114 n and marking 1310 of thetulip 1310. When the markings/cutouts 1303 and 1310 are aligned, thestart 1302 of the threads 1304 on the locking cap 114 n is close toengaging the start 1306 of the threads 1308 on the inner surface 112 dof the tulip 1310. This allows a user to quickly and repeatably engagethe threads 1304 of the locking cap 114 n with the inner surface 112 dof the tulip 1310. The tulip 1310 may have a rounded slot 1312 to acceptthe spinal rod 118 such that the spinal rod 118 is perpendicular to thethreads 1304 of the locking cap 1302.

FIG. 14 illustrates the tulip 1310 in accordance with particularembodiments of the present disclosure. The sides 1400 of the tulip 1310may be shaped as a concentric cylinder which taper towards the bottom1402 of the tulip 1310. A front side 1404 and back side (not shown) areflat, with an upper flat portion 1406 being narrower in width than alower flat portion 1408.

FIG. 15 illustrates a tulip 1500 in accordance with particularembodiments of the present disclosure. The tulip 1500 may be similar tothe tulip 1310 as shown on FIG. 14. The tulip 1500 may include a largeradii or flat portion 1502 on a side 1504 of the tulip 1500. The flatportion 1502 may improve alignment with mating instruments (not shown).

FIG. 16A illustrates a cross-section of a clamp assembly 1600 a inaccordance with particular embodiments of the present disclosure. Theclamp assembly 1600 a may include a tulip 1602, a spherical head 1604 ofa bone screw, and a saddle 1606.

The saddle 1606 may be movably disposed within an opening 1607, asshown. The saddle 1606 may be an elongated rigid member with a shapesimilar to the tulip 1602. The saddle 1606 includes an opening 1608 at afirst end 1610 and an opening 1612 positioned opposite to the opening1608 at a second end 1614, as shown. The saddle 1606 may include a ridge1616 that projects into a recess 1618 extending along an inner surface1620 of the tulip 1602, thereby preventing movement of the saddle 1606beyond the recess 1618, as shown. The bone screw 1604 may be disposedwithin the tulip 1602 and the opening 1612. The opening 1612 may includecurvature that corresponds with the shape of the spherical head 1604 tofacilitate securing of the spherical head 1604 within the clamp assembly1600 a, as shown. An internal taper 1619 of the tulip 1602 may retainthe spherical head 1604. The polyaxial motion is locked when the spinalrod 118 (e.g., shown on FIG. 13) compresses into the saddle 1606 whichcompresses against the spherical head 1604 of the bone screw.

FIG. 16B illustrates a cross-section of a clamp assembly 1600 b and aclip 1620 in accordance with particular embodiments of the presentdisclosure. The clip 1620 may be used to retain the spherical head 1604within the tulip 1602 instead of the internal taper 1619 (shown on FIG.16A) of the tulip 1602. The clip 1620 may be disposed within an internalrecess 1621 of the tulip 1602.

FIG. 16C illustrates a cross-section of a clamp assembly 1600 c withcircumferential lips 1622 in accordance with particular embodiments ofthe present disclosure. To create a ring of contact between a saddle1606 a and the spherical head 1604, one or more circumferential lips1622 on the saddle 1606 a or an internal taper 1624 of the saddle 1606 amay contact the spherical head 1604.

FIGS. 17A and 17B illustrate a tulip 1700 and a saddle 1704 inaccordance with particular embodiments of the present disclosure. Thespherical head 1604 (shown on FIG. 16C) of the bone screw may beinserted into the tulip 1700 and the clip 1620 (shown on FIG. 16B) maybe inserted into an internal groove 1702 of the head to retain thespherical head 1604. The saddle 1704 (shown on FIG. 17B) is theninserted from a top 1701 of the tulip 1700 with a spinal rod slot 1706 b90° out of alignment with the rod slot of the tulip 1706 a. The saddleis then rotated into the internal groove 1702 so that the rod slots 1706a and 1706 b are aligned. An upper profile (e.g., an upper profile 1708shown on FIG. 17B) of the saddle 1704 and the internal groove 1702 areelliptically shaped to prevent the saddle 1704 from rotating out ofalignment. Relief cuts 1710 in the tulip 1700 allow rotation of thesaddle 1704 into alignment only in one direction. Grooves 1712 cut intothe saddle 1704 allow for an interface with an assembly tool (not shown)to facilitate rotation.

FIG. 18 illustrates a cross-section of a clamp assembly 1800 includingthe tulip 1700 in accordance with particular embodiments of the presentdisclosure. In this embodiment, the saddle 1704 may be inserted into thetulip 1700 from the bottom 1808 and pressed past a retaining bump 1806.The spherical head 1604 of the bone screw is then inserted from a bottom1808 of the tulip 1700 into contact with the saddle 1704 and the clip1620 inserted from the bottom 1808 to retain the spherical head 1604.The saddle 1704 is then pressed down past the retaining bump 1806. Theretaining bump 1806 and elliptical shape of the saddle 1704 and theinternal groove 1702 prevent the saddle 1704 from moving upward androtating.

FIG. 19A illustrates a clamp assembly 1900 in accordance with particularembodiments of the present disclosure. The clamp assembly 1900 may besimilar to the clamp assembly 1800. In this embodiment, instead of anellipse, internal flat portions 1901 of the tulip 1902 are positioned oneither side of flat portions 1903 (also shown on FIG. 19B) of a saddle1904 to restrict rotation of the saddle 1904 within the spinal rod slot1906.

FIG. 19B illustrates the saddle 1904 in accordance with particularembodiments of the present disclosure. The saddle 1904 includes the flatportions 1903 to correspond with the flat portions 1901 of the tulip1902 (shown on FIG. 19A).

FIG. 20A illustrates a bottom 2000 of a tulip 2002 in accordance withparticular embodiments of the present disclosure. In this embodiment, ascrew 2004 (shown on FIG. 20B) is inserted from a top (e.g., the top1701 shown on FIG. 17A) of the tulip 2002 until it contacts an internaltapered portion 2006 at the bottom 2000. A saddle (e.g., the saddle 1904shown on FIG. 19B) may then be inserted from the top of the tulip 2002and rotated into alignment with a spinal rod slot (e.g., similar to thespinal rod slot 1706 a shown on FIG. 17A). Threads 2008 cut into thetaper portion 2006 are shaped to allow the largest screw possible tothread through the tulip 2002.

FIG. 20B illustrates the bottom 2000 of the tulip 2002 with the screw2004 in accordance with particular embodiments of the presentdisclosure. The screw 2004 extends through a passage 2010 positionedthrough the bottom 2000 of the tulip 2002.

FIGS. 21A and 21B illustrate a bone screw 2100 in accordance withparticular embodiments of the present disclosure. The spherical head1604 of the bone screw 2100 may be inserted into the tulip 2102 beforebeing assembled to the threaded portion 2104 of the bone screw 2100. Thethreaded portion 2104 of the bone screw 2100 may be retained in thespherical head 1604 by a snap retaining fit, a press fit, a pin,threads, or some combination of retaining features (e.g., retainingfeature 2106).

FIG. 21B illustrates the spherical head 1604 separated from the threadedportion 2104 of the bone screw 2100 in accordance with particularembodiments of the present disclosure. The threaded portion 2104 of thebone screw 2100 may be retained in the spherical head 1604 by a snapretaining fit, a press fit, a pin, threads, or some combination ofretaining features (e.g., retaining feature 2106).

FIG. 22A illustrates a clamp assembly 2200 in accordance with particularembodiments of the present disclosure. The tulip 2202 may be a uniplanartulip and may include a uniplanar screw 2204. The uniplanar tulip 2202may have a through hole 2206 which contacts pivots (e.g., pivots 2207shown on FIG. 22B) on the head of the screw 2204 and allows the head2208 to pivot either along a spinal rod slot 2210 or perpendicular tothe spinal rod slot 2210 depending on the orientation of the throughhole 2206. A saddle 2208 compresses against the head 2208 when locked,restricting motion.

FIG. 22B illustrates a cross-section of the clamp assembly 2200, takenalong a dashed line extending between A and A′, in accordance withparticular embodiments of the present disclosure. As previouslymentioned, the pivots 2207 allows the head of the screw 2204 to pivoteither along the spinal rod slot 2210 (shown on FIG. 22A) orperpendicular to the spinal rod slot 2210. Teeth, groove cuts, or aroughened surface 2212 may increase the grip of this interface.

FIG. 23 illustrates a monoaxial screw 2300 in accordance with particularembodiments of the present disclosure. The monoaxial screw 2300 combinesa screw head (e.g., head 2208 shown on FIG. 22A) with the bone screwportion 2304 into a single component to form the monoaxial screw 2300.

FIG. 24A illustrates a clamp assembly 2400 in accordance with particularembodiments of the present disclosure. The clamp assembly 2400 mayinclude a spherical screw head 2402 of a bone screw 2404 that issplined. The splines on the spherical head 2402 of the bone screw may becut to follow the spherical profile of the spherical head. The sphericalscrew head 2402 may be positioned into the tulip 2406 via an opening2407 at a bottom 2408 of the tulip 2406. The spinal rod 118 may becompressed between a locking cap 2410 and a saddle 2412. The opening2407 may include conical splines 2409 to mate with splines (e.g.,splines 2403 shown on FIG. 24B) of the spherical screw head 2402.

FIG. 24B illustrates a top view of the spherical screw head 2402 inaccordance with particular embodiments of the present disclosure. Thesplines 2403 on the spherical screw head 2402 includes a circularprofile and may mate with similarly shaped splines 2409 cut into theopening 2407 (shown on FIG. 24A). These splines 2403 do not allow thetulip 2402 to rotate about the bone screw 2404, but permit medial andlateral angulation. Axial torque can be transmitted to the bone screw2404, allowing the bone screw 2404 to be driven or reversed withoutengaging a drive feature, (e.g., drive feature shown on FIGS. 4A and 4B)or by an instrument (not shown) not positioned coaxially with the bonescrew.

Various instrument interfaces may be used for engaging insertion,positioning, reduction, and derotation instruments. The bone screw(e.g., the bone screw 2404) may include a hex, hexalobe, or modifiedhexalobe in the spherical screw head for driving the bone screw into abone. Features on the tulips in the embodiments below may be engaged byinstruments with corresponding tabs or grooves which collapse, pivot,slide, or flex into engagement with the tulip for insertion,positioning, reduction, and derotation.

FIG. 25A illustrates an inner surface 2500 a of a tulip (e.g., similarto the tulip 102 shown on FIG. 1) in accordance with particularembodiments of the present disclosure. In this embodiment cylindrical,elliptical, or linear grooves 2502 a may be cut into the inner surface2500 a to receive a instrument (not shown).

FIG. 25B illustrates an inner surface 2500 b of a tulip (e.g., similarto the tulip 102 shown on FIG. 1) in accordance with particularembodiments of the present disclosure. In this embodiment cylindrical,elliptical, or linear grooves 2502 b may be cut into the inner surface2500 b to receive a driving instrument (not shown). As shown, the lineargrooves 2502 b are smaller (e.g., shorter and/or shallower) in size thanthe linear grooves 2502 a of FIG. 25A.

FIG. 26A illustrates a tulip 2600 in accordance with particularembodiments of the present disclosure. The tulip 2600 may include anupper outer section 2602 a that includes a ledge, lip, or groove 2604 a,as shown.

FIG. 26B illustrates a portion 2606 a of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 a may include an upper outersection 2602 b that includes a lip 2604 b and a groove 2608 a thatincludes an upper surface 2609 a that is angled inward, as shown. Abottom surface 2610 a is horizontal. The inward angle preventsdisengagement of an instrument (not shown) under axial reduction loads.

FIG. 26C illustrates a portion 2606 b of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 b may include an upper outersection 2602 c that includes the lip 2604 b and a groove 2608 b thatincludes the upper surface 2609 a that is angled inward, as shown. Abottom surface 2610 b is angled outward. The inward angle preventsdisengagement of an instrument (not shown) under axial reduction loads.

FIG. 26D illustrates a portion 2606 c of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 c may include an upper outersection 2602 d that includes a lip 2604 c and a groove 2608 c thatincludes an upper surface 2609 b that is flanged, as shown. The bottomsurface 2610 a is flat. The flange prevents disengagement of aninstrument (not shown) under axial reduction loads.

FIG. 26E illustrates a portion 2606 d of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 d may include an upper outersection 2602 e that includes a lip 2604 d and a groove 2608 d thatincludes the upper surface 2609 b that is flanged, as shown. The bottomsurface 2610 a is angled outward. The flange prevents disengagement ofan instrument (not shown) under axial reduction loads.

FIG. 26F illustrates a portion 2606 e of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 e may include an upper outersection 2602 f that includes the lip 2604 e and a groove 2608 e thatincludes the upper surface 2609 a that is angled inward, as shown. Abottom surface 2610 e is angled inward. The inward angles preventdisengagement of an instrument (not shown) under axial reduction loads.

FIG. 26G illustrates a portion 2606 f of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 f may include an upper outersection 2602 g that includes the lip 2604 a without a bottom surface.

FIG. 26H illustrates a portion 2606 g of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 g may include an upper outersection 2602 h that includes a lip 2604 g and a groove 2608 f thatincludes the upper surface 2609 b that is flanged, as shown. A bottomsurface 2610 f is also flanged. The flanges prevent disengagement of aninstrument (not shown) under axial reduction loads.

FIG. 26i illustrates a portion 2606 h of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 h may include an upper outersection 2602 i that includes a lip 2604 h and a groove 2608 g. Across-section of the groove 2608 g is circular with a depth greater thanthe radius of the groove to prevent disengagement of an instrument (notshown) under axial reduction loads.

FIG. 26j illustrates a portion 2606 i of a tulip (e.g., similar to thetulip 2600 shown on FIG. 26A) in accordance with particular embodimentsof the present disclosure. The portion 2606 i may include an upper outersection 2602 j that includes a lip 2604 i and a groove 2608 h, as shown.A second groove 2612 may be disposed on a top of the portion 2606 i, asshown, to allow insertion of a tip of an instrument (not shown) toresist outward splaying forces under axial reduction loads.

FIG. 26K illustrates a section view of an upper portion of FIGS. 26B-Jin accordance with particular embodiments of the present disclosure. Asshown, upper portion 2614 which may include the upper portion 2604 cand/or 2604 d may be cylindrical.

FIG. 27 illustrates a tulip 2700 in accordance with embodiments of thepresent disclosure. The tulip 2700 may be similar to the tulip 102(shown on FIG. 1). The tulip 2700 may include front portions 2702 a and2702 b that include vertical slots 2704 a and 2704 b which are engagedby corresponding tabs on an instrument. A rear portion (not shown) maybe similar to the front side (shown).

FIG. 28 illustrates a tulip 2800 in accordance with embodiments of thepresent disclosure. The tulip 2800 may be similar to the tulip 102(shown on FIG. 1). The tulip 2800 may include side portions 2802 a and2802 b. The side portion 2802 a includes a circular pocket 2804 a whichis engaged by corresponding tabs on an instrument. The side portion 2802b may be similar to the side portion 2802 a.

FIG. 29 illustrates a tulip 2900 in accordance with embodiments of thepresent disclosure. The tulip 2900 may be similar to the tulip 102(shown on FIG. 1). The tulip 2900 may include side portions 2902 a and2902 b. The side portion 2902 a includes a chevron which is engaged bycorresponding tabs on an instrument. The side portion 2902 b may besimilar to the side portion 2902 a.

FIG. 30 illustrates a tulip 3000 in accordance with embodiments of thepresent disclosure. The tulip 3000 may be similar to the tulip 102(shown on FIG. 1). The tulip 3000 may include a threaded upper portion3002 that may be extended to allow a spinal rod (e.g., the spinal rod118 shown on FIG. 13) to be captured and reduced into the tulip 3000 bythreading a locking cap (e.g., the threaded locking cap 114 shown onFIG. 1). Internal and/or external grooves 3004 a-3004 f allow forextended tabs 3006 a-3006 h to be broken away from the tulip 3000 oncethey are no longer needed. The multiple grooves 3004 a-3004 f atdifferent heights allow tabs 3006 a-3006 h to be broken at a desiredheight to reduce the amount of turns necessary to turn the locking cap,or prevent contact with adjacent implants.

FIG. 31A illustrates a tulip 3100 in accordance with embodiments of thepresent disclosure. The tulip 3100 may be similar to the tulip 3000(shown on FIG. 30). In this embodiment, a hole 3102 through a side of atab 3006 i allows for passage of a cable 3104. When looped around thespinal rod 118 or a mating instrument 3106, tensioning of the cable 3104reduces the spinal rod 118 into the tulip 3100 before being captured bya locking cap 3108. In certain embodiments, the holes 3102 may be insides 3103 of the tulip 3100 without the tab 3006 i.

FIG. 31B illustrates a close-up of the tulip 3100 in accordance withembodiments of the present disclosure. As shown, the cable 3104 ispositioned about the spinal rod 118 and extends through the tulip 3100.

The present disclosure as described above describes many features whichallow improved functionality, strength, and ease of manufacturing for apedicle screw head. The locking cap designs describe thread geometriesthat improve strength, reduce outward splaying forces on the screw head,increase resistance to cross-threading, allows quick engagement of thelocking cap, a more consistent interface with mating instruments, andcontacts with the spinal rod to increase gripping strength. The internalcomponent designs describe multiple features to al low simplifiedgeometries to reduce profile, increase polyaxial strength, and simplifymanufacturing and assembly. The uniplanar, monoaxial, and axiallyconstrained polyaxial screw designs allow for rigidity in variousdirections to allow the user to transmit forces to the vertebral bodyfor correction or screw insertion. The instrument interfaces describe avariety of features to allow instruments to interface from severaldirections, provide increased holding strength, decrease splaying forceswhich would cause disengagement of instruments, and simplifymanufacturing. The reduction tab designs allow for a new method forreducing the rod into the screw head.

It is believed that the operation and construction of the presentdisclosure will be apparent from the foregoing description. While theapparatus and methods shown or described above have been characterizedas being preferred, various changes and modifications may be madetherein without departing from the spirit and scope of the disclosure asdefined in the following claims.

What is claimed is:
 1. A clamp assembly comprising: a tulip comprisingan opening comprising an inner surface, wherein the inner surface isthreaded; and a threaded locking cap disposed in the opening.
 2. Theclamp assembly of claim 1, wherein top surfaces and bottom surfaces ofthreads of the locking cap are rectangular.
 3. The clamp assembly ofclaim 2, wherein top surfaces and bottom surfaces of threads of theinner surface are rectangular.
 4. The clamp assembly of claim 1, whereintop surfaces and bottom surfaces of threads of the inner surface areangled.
 5. The clamp assembly of claim 1, wherein top surfaces andbottom surfaces of threads of the locking cap are angled.
 6. The clampassembly of claim 1, wherein top surfaces of threads of the innersurface are rectangular and wherein bottom surfaces of threads of theinner surface are angled.
 7. The clamp assembly of claim 6, wherein topsurfaces of threads of the threaded locking cap are rectangular andwherein bottom surfaces of threads of the locking cap are angled.
 8. Aclamp assembly comprising: a tulip comprising an opening comprising aninner surface, wherein the inner surface is threaded; and a threadedlocking cap disposed in the opening, wherein the threaded locking capincludes a drive feature.
 9. The clamp assembly of claim 8, wherein thedrive feature includes a hexalobe drive feature.
 10. The clamp assemblyof claim 8, wherein the drive feature includes a modified hexalobe drivefeature comprising inner lobes of a hexalobe truncated by a circle. 11.The clamp assembly of claim 8, wherein the drive feature comprisesgrooves configured to receive prongs of a driving instrument.
 12. Theclamp assembly of claim 8, wherein the drive feature comprises a grooveconfigured to receive a split ring of a driving instrument.
 13. Theclamp assembly of claim 8, wherein a bottom of the threaded locking capcomprises a tapered flat portion.
 14. The clamp assembly of claim 8,wherein a bottom of the threaded locking cap comprises a rounded bump.15. The clamp assembly of claim 8, wherein a bottom of the threadedlocking cap comprises a rounded ring configured to contact a spinal rodat two points.
 16. The clamp assembly of claim 8, wherein a bottom ofthe threaded locking cap comprises a groove configured to seat on aspinal rod.
 17. The clamp assembly of claim 8, wherein a bottom of thethreaded locking cap comprises a contact component made of a differentmaterial than the threaded locking cap.
 18. The clamp assembly of claim8, wherein an outer surface of the tulip comprises grooves configured toreceive a driving instrument.
 19. A clamp assembly comprising: a tulip,wherein an inner surface of the tulip comprises threads; and a drivefeature positioned in an outer portion of the tulip, the drive featureconfigured to receive a driving instrument.
 20. The clamp assembly ofclaim 19, wherein the feature comprises a pocket in a shape of achevron, a vertical slot, or a circle.